Document Type
Article
Publication Date
7-2026
Department
College of Forest Resources and Environmental Science
Abstract
Migratory songbird populations are declining across North America, and collisions with glass-fronted buildings have become one of their leading causes of mortality. Finding practical ways to curb these collisions is a key conservation priority, but large-scale solutions remain elusive because retrofitting glass façades and enforcing lights-out policies are often prohibitively costly and logistically difficult. In this study, we focused on developing low-cost alternative deterrents that redirect migrants away from high-risk areas. We tested two acoustic deterrents: a broadband synthetic signal designed to mask nocturnal flight calls, which are important social cues for migrants, and a “predator” track featuring alarm calls and local raptor vocalizations. Their effects were first assessed at five forest-meadow stopover sites in Michigan’s Upper Peninsula during spring 2023. We used autonomous recorders recording migrant flight calls as a measure of migrant activity before and after deterrent playback. Autonomous recorders showed a 42% drop in migrant detections during synthetic playback and a 20% decline during predator playback. We then applied a before– after control–impact design on Northwestern University’s Lake Michigan campus, focusing on four buildings that historically register the most strikes. A hierarchical zero-inflated Poisson model controlling for migration intensity and building identity revealed that predator and synthetic broadcasts cut collisions by 56% and 68%, respectively, in 2023, when both units suffered occasional malfunctions. In 2024, predator deterrents operated continuously resulting in an 89% decrease in collisions. Our results suggest that acoustic deterrents represent a practical and scalable pathway to large reductions in passage migrant building collisions.
Publication Title
Avian Conservation and Ecology
Recommended Citation
Brewer, J.,
Oberloier, S.,
Prince, A.,
Stone, D.,
&
Wolfe, J.
(2026).
Evaluating acoustic deterrents for reducing migratory bird collisions with buildings.
Avian Conservation and Ecology,
21(2).
http://doi.org/10.5751/ACE-03143-210205
Retrieved from: https://digitalcommons.mtu.edu/michigantech-p2/2914
Creative Commons License
This work is licensed under a Creative Commons Attribution 4.0 International License.
Version
Publisher's PDF
Publisher's Statement
Copyright © 2026 by the author(s). Publisher’s version of record: https://doi.org/10.5751/ACE-03143-210205